12 



NORTH AMEEICAX FAUNA. 



[No. 40, 



List of Species and Subspecies with Type Localities. 



Subgenus CYNOMYS. 



Cynomys ludovicianus ludovicianus (Ord) Upper Missouri River. 



ludovicianus arizonensis Mearns Point of Mountain, Arizona. 



mexicanus Merriam La Ventura, Coahuila, Mexico. 



Subgenus LEUCOCROSSUROMYS. 



Cynomys leucurus Merriam Fort Bridger, Wyoming. 



parvidens Allen Buckskin Valley, Utah. 



gunnisoni gunnisoni (Baird) Cochetopa Pass, Colorado. 



gunnisoni zuniensis nobis Wingate, New Mexico. 



Key to Species and Subspecies. 



a.^ Tail tipped with black; jugal bone heavy, thickened, the outer face at angle of 

 ascending branch presenting a broad triangular surface (Cynomys). 

 b.^ Black on tail covering most of distal half; tail longer; audital bullae large and 

 greatly inflated ; posterior border of inflected angle of mandible nearly at right 



angle to axis of jaw C. mexicanus (p. 21). 



&,2 Black on tail confined to distal third; tail shorter; audital bullae smaller and less 

 inflated; posterior border of inflected angle of mandible at angle of about 

 45° to axis of jaw. 



c.^ Coloration above in fresh summer pelage dark pinkish cinnamon; audital 

 bullae smaller; anterior face of maxillary root of zygoma deeply emerginate, 



C. 1. ludovicianus (p. 14). 



C.2 Coloration above in fresh summer pelage more vinaceous-cinnamon; audital 

 bullae larger; superior surface of maxillary root of zygoma very broad, not 



deeply emarginate anteriorly C. 1. arizonensis (p. 19). 



G.2 Tail tipped and bordered with white; jugal bone weak, thin, and flat, the outer 

 surface at angle of ascending branch only very slightly thickened, the margin 

 rounded, not distinctly triangular (Leucocrossuromys) . 

 Terminal half of tail white, without dark center, 

 c.^ Size larger; coloration in summer buffy or grayish (not reddish or rich cinna- 

 mon); skull with less interorbital breadth C. leucurus (p. 24). 



C.2 Size smaller; coloration in summer reddish or rich cinnamon (not buffy or 



grayish); skull with greater interorbital breadth C. parvidens (p. 27). 



5.2 Terminal half of tail with gray center, bordered and tipped with white. 

 c} Size smaller, with smaller hind foot; coloration more buffy and blackish, less 



pinkish cinnamon and ochraceous C. g. gunnisoni (p. 29). 



C.2 Size larger, with larger hind foot; coloration more pinkish cinna^^on and 

 ochraceous, less buffy and blackish C. g. zuniensis (p. 32). 



Subgenus CYNOMYS Eafinesque. 



Characters. — Size large; tail comparatively long, averaging more 

 than one-fifth the total length, and tipped with black; mammae 8. 

 SJiuU: Angular and massive ; general shape of occipital region, viewed 

 from behind, oval; jugal bone heavy, thickened, the outer surface 

 at angle of ascending branch very broad, triangular, with inferior 

 v-ertex produced far downward; maxillar}^ root of zygoma corre- 

 spondingly strengthened, the shelf and supra jugal arm much thick- 

 ened. Teeth larger, more expanded laterally, than in species of the 

 white-tailed group. 



